Unleaded vs Lead Replacement Petrol

[Mr_B]

Hi all,

The fam and I went on really enjoyable farm holiday this weekend, travelled 250km to just outside Heidelberg... I decided to do a little test on the open road... before leaving Cape Town i filled up with 95 LRP... my lux ran pretty well, but did feel a little underpowered/sluggish on the longer uphills especially on the R60 between Ashton on Swellendam... we cruised at around 95-110km/h... traffic dependant... fuel consumption was good... just over 8km/l... 200km or so on 24 litres of fuel... for a 2.2 4Y, pretty loaded with baggage, running 33's... this is pretty good! We had a great weekend (I'll post pics later)... then leaving on Sunday, I drove until the tank was below 1/4 full... and then filled up in Robertson with 95 unleaded... the difference was almost immediate, power/torque was significantly better... cruising @ 120km/h+ was suddenly effortless, with very little speed loss on the longer uphills... I landed up towing a stranded couple and their blown head gasket Volvo back to Cape Town, from just outside Worcester... back to Brackenfell... only had to use 3rd gear once, due to uphill and slow moving traffic... so I'm not sure about the fuel consumption on ULP, but I got back home with a half tank left so it didn't look too bad!

To cut to the case... has anyone else noticed the power difference between LRP and ULP??

I will certainly be running my 4Y on ULP only in future!

mr b

[Muz]

shew, i think mine seems to have better fuel consumption on LRP. 2.4 Petrol. Fuel consumption has been a bit difficult to determin as had the aircon on now and then, but the unleaded i think doesn't last as long.

[Mountain Man]

I can't say I have noticed a difference between the LRP and ULP but what I have noticed a difference with is the 93 ULP and 95 ULP. That was when I had my carb but since I have had the fuel injection I have not driven much, maybe 180Km so have not had the chance to compare.

[Asterix]

That is a very interesting post that baffled me big time

I am a design engineer at a motor manufacturing company - I did fuel systems a few years ago. According to the fuel company's there should be no difference in performance.
Unleaded fuel can get "old" faster due to less stuff they mix in and make it evaporate faster, but that is about it.

Are you sure the octane rating for the leaded and unleaded fuels were the same?

[Mr_B]

Johan, we only have 95 octane in Cape Town and surrounds, unlike up country where 93 is also available!

I guess the only way to prove the percieved difference is to put the vehicle on a dyno... and compare the nm/kw stats from the 2 runs, one on ULP and the other on LRP... Is it not possible that the LRP was contaminated with something? I remember a few months ago my wife filled up one evening, the following morning I pulled the car out, and smelt a definite diesel smell, the petrol was possibly contaminated with a little diesel... in fact the Golf engine ran very happily on the compromised mix! After the mix fill-up the diesel smell was gone!

mr b

[Asterix]

That is definitely a possibility.
I saw a Total truck filling Engen tanks late at night. Who knows what is exactly in the tanks at the filling station?

[Moeraspadda]

is it ok to run unleaded on these old motors?

[Mr_B]

According the data I can find online the answer is yes, take a look at this AUS website:

http://www.aip.com.au/health/lead_guide.htm

BTW this has been discussed before... read here:

viewtopic.php?f=3&t=1396&p=12344

I use ULP on my 4Y, bearing in mind I have had the head rebuilt completely, and have new valves and seats!

mr b

[BenHur]

Brets

You are absolutely right in your assumption I have seen this on more then on Lux that they run cleaner on ULP and then perform better as well.


I think LRP is just ULP filled with a lot of extra poefies.

[Mud Dog]

Until you burn the valve seats, then you wish you had used the LRP with all the "poefies" additives. An occasional top up with ULP in an old 4y that has'nt had the valve seats replaced should'nt be a problem, but I would'nt use it continually. As said before, better safe than sorry.

[ThysdJ]

I agree Andy, unless I am really sure what goes on inside an old engine like that in my vehicle, I would err on the side of caution and use LRP. If you know the valve seats etc on your old engine were replaced with the proper atties then go for it...

Naah they must be deurmekaar, Toy SA would not be so stupid as to still use valve stem seals that needs lead or lead replacement as lubricant, must be someone's misinterpretation.

I would not be so sure hey, if it meant they could save money in the manufacturing process and pass the cost on to the consumer, they would do just that.

[Hoppy]

We have tested it in our racing carts where you can feel and see a little power difference in the lap times, unleaded is definately tops.

[Asterix]

Bret,

Replace your engine with a Diesel one.
This post starts to sound like serious science!

[Mr_B]

Bret,

Replace your engine with a Diesel one.
This post starts to sound like serious science!

Asterix... if I do so... do I use 500PPM sulphur or 50PPM sulphur diesel... cause I've heard of alot of guys replacing the diesel injectors cause the engine was designed for 50PPM and they used 500PPM... simply because 50PPM is not so readibily available... the cost of replacing injectors on a diesel is exhorbitant... a D4D's injectors are something like R 20 000+... actually you know what I think I'll stick to a 4Y petrol, if I fry the valve stem seals... I can get that fixed for less then R 2000... or buy an recon'd original Toyota head for R2150... so a petrol engine wins for me! Viva 4Y viva!

mr b

[Asterix]

You're right Brett,

I was just teasing.

Nothing wrong with petrol. The new Diesel technology is a real pain if one has to replace parts.

However, I like the old donkey mechanical diesel engines that one can still run on paraffin. It sounds and feels like a real truck and the torque is just great. Just personal taste!

My apologies - didn't mean to cause too much crap!

[Mr_B]

You're right Brett,

I was just teasing.

Nothing wrong with petrol. The new Diesel technology is a real pain if one has to replace parts.

However, I like the old donkey mechanical diesel engines that one can still run on paraffin. It sounds and feels like a real truck and the torque is just great. Just personal taste!

My apologies - didn't mean to cause too much crap!

Hey if you don't stir... the sugar won't dissolve in your coffee... bitter coffee... no thanks!

Keep Stirring! No apologies needed!

mr b

[chopper]

Dankie Johan,
Ek't ook nie meer geweet watter kant toe met al die redenasies en HOMKAs nie!

[Asterix]

Ek't ook nie meer geweet watter kant toe met al die redenasies en HOMKAs nie!

Jis nou voel ek nie meer sleg nie. Ek is maar redelik dom - dis seker maar die hoof rede hoekom ek 'n ou diesel enjin in my Lux ingebou het wat met alles wat amper soos diesel lyk (behalwe ratkas olie - die goed is te dik) kan werk. :problem:

[chopper]

Ja,
Ek't nou vir my 'n 2.2 SFA gekoop wat nog baie mooi loop maar 'n "oil-burner" sal 'n sterk oorweging wees indien die 2.2 vorentoe moeg raak!

[Asterix]

Thinus,

Kyk bietjie vir www.engineden.co.za -daar is pryse op hulle website.
Ek het al 'n hele paar jap import engines in voertuie in gebou en was heel gelukkig. Vir die prys wat mens die goed kry vervang ek eerder die hele enjin as om te sukkel en hope geld spandeer om 'n stuk scrap reg te maak. Al kry mens net 50 000km uit die enjin is dit nog steeds die geld en moeite werd.

Die lekker deel van dit is - jy sit in wat jy in wil he. Jis, ek het amper 'n Supra motor in my bakkie in gebou, maar die vrou het nie baie van die idee gehou nie.

[Mr_B]

Ja,
Ek't nou vir my 'n 2.2 SFA gekoop wat nog baie mooi loop maar 'n "oil-burner" sal 'n sterk oorweging wees indien die 2.2 vorentoe moeg raak!

Thinus... jy gat lank wag voor daai 4Y moeg word!

[chopper]

Ek hoop werklik so!

[legend35]

Ek stem saam met jou Johan.Ek het een van daai imports in my Honda en geen probleme.